Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description is fully consistent with them ("this tool is read-only coverage only"). It adds real behavioral value beyond the annotations by disclosing that the listing is activity-level only and that entry reading/adding is out of scope for the server, preventing a failed call pattern.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with the capability front-loaded and the scope limit second, which is the right ordering. The closing clause 'read-only coverage only' is slightly redundant with the opening 'List', costing a bit of tightness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need not be described, and the single required param is fully specified in the schema. What remains adequately covered is the read-only, activities-not-entries boundary; only a pointer to the alternative for entry data would improve it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and the single param (course_ids) is fully documented in the schema, so the baseline of 3 applies. The phrase "one or more courses" lightly corroborates that the parameter accepts multiple ids, but adds no syntax or format detail beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (List) and resource (Database "mod_data" activities) with scope ('across one or more courses'), which is enough to separate it from unrelated siblings like get_course_contents or list_quizzes. It does not, however, explicitly contrast itself with the many other list_* siblings (list_lessons, list_h5p_activities, etc.) that share the same pattern.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description scopes the tool by exclusion ("Reading/adding entries is not supported by this server"), which tells the agent this is list-only and cannot fetch entry contents. It gives no positive when-to-use trigger and names no alternative sibling for the entry-level data, leaving the routing decision partly inferred.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.